A dodecameric self-assembled calix[4]arene aggregate with two types of cavities.

Twelve molecules of β-carbonyl-para-octyl-calix[4]arene assemble in an aggregate containing two types of cavities filled by water molecules and they pack in a cubic structure. Both the aggregates and the packing resemble that observed for inverse micelles.

1-Butyl-quinine tetra-fluoro-borate.

In the title salt (2S,4S,8R)-1-butyl-2-[(R)-(hydr-oxy)(6-methoxy-quinolin-4-yl)meth-yl]-8-vinyl-quinuclidin-1-ium tetra-fluoro-borate, C(24)H(33)N(2)O(2) (+)·BF(4) (-), the butyl substituent at the 1-position is in an equatorial conformation with respect to the unsubstituted six-membered ring and the four butyl C atoms are almost coplanar with the ring N and vinyl C atoms (r.m.s.

Probability plots based on Student's t-distribution.

The validity of the normal distribution as an error model is commonly tested with a (half) normal probability plot. Real data often contain outliers. The use of t-distributions in a probability plot to model such data more realistically is described.

Determination of experimental charge density in model nickel macrocycle: [3,11-bis(methoxycarbonyl)-1,5,9,13-tetraazacyclohexadeca-1,3,9,11-tetraenato-(2-)-kappa(4)N]nickel(II).

Experimental and theoretical atomic charges and d-orbital populations were obtained for [3,11-bis(methoxycarbonyl)-1,5,9,13-tetraazacyclohexadeca-1,3,9,11-tetraenato(2-)-kappa(4)N]nickel(II) monocrystal (16Ni) using the Hansen and Coppens formalism. Several models of this structure were tested as a function of quality of the fit, convergence of the refinement, value of residual peaks and holes, and Hirshfeld's rigid-bond test. The models with Ni-atomic scattering factors applied for the metal center are significantly better than those with the Ni-ionic scattering factors.

Determination of absolute structure using Bayesian statistics on Bijvoet differences.

A new probabilistic approach is introduced for the determination of the absolute structure of a compound which is known to be enantiopure based on Bijvoet-pair intensity differences. The new method provides relative probabilities for different models of the chiral composition of the structure. The outcome of this type of analysis can also be cast in the form of a new value, along with associated standard uncertainty, that resembles the value of the well known Flack x parameter.